xref: /freebsd/usr.bin/random/random.6 (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
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28.\"     @(#)random.6	8.2 (Berkeley) 3/31/94
29.\" $FreeBSD$
30.\"
31.Dd February 15, 2020
32.Dt RANDOM 6
33.Os
34.Sh NAME
35.Nm random
36.Nd random lines from a file or random numbers
37.Sh SYNOPSIS
38.Nm
39.Op Fl elrUuw
40.Op Fl f Ar filename
41.Op Ar denominator
42.Sh DESCRIPTION
43.Nm Random
44has two distinct modes of operations.
45The default is to read lines from standard input and write them to standard
46output with a probability of 1.0 /
47.Ar denominator .
48.Ar ( denominator
49is a real number greater than or equal to 1.0.)
50The default
51.Ar denominator
52for this mode of operation is 2.0, giving each line a 50% chance of
53being displayed.
54.Pp
55The second mode of operation, selected with the
56.Fl f Ar filename
57option, reads the specified file and outputs the randomized contents to
58standard output.
59The contents can be randomized in units of lines (split on newline characters)
60or in units of words (split on space characters as determined by
61.Xr isspace 3 . )
62The default
63.Ar denominator
64for this mode of operation is 1.0, which displays every line.
65.Pp
66The options are as follows:
67.Bl -tag -width Ds
68.It Fl e
69If the
70.Fl e
71option is specified,
72.Nm
73does not read or write anything, and simply exits with a random
74exit value of 0 to
75.Ar denominator
76\&- 1, inclusive.
77In this mode,
78.Ar denominator
79must be less than or equal to 256.
80.It Fl f Ar filename
81The
82.Fl f
83option is used to specify the
84.Ar filename
85to read from.
86Standard input is used if
87.Ar filename
88is
89.Sq - .
90.It Fl l
91Randomize the input via newlines (the default).
92.It Fl r
93Do not buffer output.
94.It Fl U
95Reuse any given line or word when creating a randomized output.
96.It Fl u
97Do not select the same line or word from a file more than once (the default).
98This does not guarantee uniqueness if there are two of the
99same tokens in the input.
100.It Fl w
101Randomize words separated by
102.Xr isspace 3
103instead of newlines.
104.El
105.Sh SEE ALSO
106.Xr fortune 6
107.Sh HISTORY
108The
109functionality to randomizing lines and words was added in 2003 by
110.An Sean Chittenden Aq Mt seanc@FreeBSD.org .
111.Sh BUGS
112This tool is a remnant of the "games" collection formerly part of
113.Fx
114base.
115It probably should have been removed to ports with the rest of that collection.
116It does not have a coherent purpose and the motivation for it to be a core base
117utility is nonobvious.
118.Pp
119No index is used when printing out tokens from the list which
120makes it rather slow for large files (10MB+).
121